A turning insert includes a head portion connected to a stem portion. A CBN cutting edge includes a surface generating cutting edge and two major cutting edge portions, such that each major cutting edge portion forms an angle of 5-20° in relation to a tangent line of the cutting edge at a forward point of the cutting edge.

A cutting tool, comprising a substrate having a cutting surface and a coating adhered to the cutting surface in a solid state, wherein the coating includes a soft metal and is capable of melting and functioning as an in-situ liquid lubricant when the cutting tool is applied in a machining operation. Also, a method of applying a coating to a cutting tool, comprising receiving a premachining workpiece, the premachining workpiece formed of a coating material including a soft metal; and machining the premachining workpiece with the cutting tool such that a layer of the coating material adheres to a cutting surface of the cutting tool in a solid state.

A cutting tool, comprising a substrate having a cutting surface and a coating adhered to the cutting surface in a solid state, wherein the coating includes a soft metal and is capable of melting and functioning as an in-situ liquid lubricant when the cutting tool is applied in a machining operation. Also, a method of applying a coating to a cutting tool, comprising receiving a premachining workpiece, the premachining workpiece formed of a coating material including a soft metal; and machining the premachining workpiece with the cutting tool such that a layer of the coating material adheres to a cutting surface of the cutting tool in a solid state.

A turning insert for machining both Inconel and Titanium workpieces. The insert includes a chip forming arrangement including only a single v-shaped groove. The groove includes a specific depth and position to improve machining of both Inconel and Titanium work pieces.

A turning insert includes a head portion connected to a stem portion. A CBN cutting edge includes a surface generating cutting edge and two major cutting edge portions, such that each major cutting edge portion forms an angle of 5-20 in relation to a tangent line of the cutting edge at a forward point of the cutting edge.

Provided is a cutter apparatus for machining a difficult-to-machine material, the cutter apparatus including: a cutting tool body which has a fastening portion formed at a center thereof; one or more cutters which are installed on the cutting tool body, and have superhard insert tips fixed to end portions thereof, respectively; and an angle adjusting unit which is installed in an internal space of the cutters, and adjusts angles of the cutters by spreading or retracting the cutters, so that angles of the cutters may be easily adjusted in accordance with a condition for cutting a difficult-to-machine material, in order to prevent damage to the superhard insert tips when machining a difficult-to-machine material having high hardness and high toughness.

A cutting tool, comprising a substrate having a cutting surface and a coating adhered to the cutting surface in a solid state, wherein the coating includes a soft metal and is capable of melting and functioning as an in-situ liquid lubricant when the cutting tool is applied in a machining operation. Also, a method of applying a coating to a cutting tool, comprising receiving a premachining workpiece, the premachining workpiece formed of a coating material including a soft metal; and machining the premachining workpiece with the cutting tool such that a layer of the coating material adheres to a cutting surface of the cutting tool in a solid state.

A turning insert for machining both Inconel and Titanium workpieces. The insert includes a chip forming arrangement including only a single v-shaped groove. The groove includes a specific depth and position to improve machining of both Inconel and Titanium work pieces.

Provided is a cutter apparatus for machining a difficult-to-machine material, the cutter apparatus including: a cutting tool body which has a fastening portion formed at a center thereof; one or more cutters which are installed on the cutting tool body, and have superhard insert tips fixed to end portions thereof, respectively; and an angle adjusting unit which is installed in an internal space of the cutters, and adjusts angles of the cutters by spreading or retracting the cutters, so that angles of the cutters may be easily adjusted in accordance with a condition for cutting a difficult-to-machine material, in order to prevent damage to the superhard insert tips when machining a difficult-to-machine material having high hardness and high toughness.

Problem: To provide a cutting tool formed from a silicon nitride-based sintered body having high fracture resistance and having residual stress of a rake face and a flank face in an appropriate range. Solution: A cutting tool (1) formed from a silicon nitride-based sintered body containing not less than 50 volume % silicon nitride-based phase and from 10 to 30 volume % titanium nitride phase, uses an intersection ridge portion of a rake face (2) and a flank face (3) as a cutting edge (4), has a residual stress applied to the titanium nitride phase that is tensile stress, and is such that the tensile stress applied to the titanium nitride phase in the rake face (2) is greater than the tensile stress applied to the titanium nitride phase in the flank face (3).